1. Technical Field
The technology disclosed herein generally relates to a lens barrel. More specifically, the technology disclosed herein relates to a retractable lens barrel used in a digital camera or the like.
2. Background Information
Recent years have witnessed the growing popularity of digital cameras that can convert an optical image of a subject into an electrical image signal and output the electrical signal. Of these, compact digital cameras in particular need to be portable, so there is an ongoing need to make the lens barrels installed in these cameras smaller.
Japanese Patent Application 2009-217243 (called “Patent Literature 1” hereinafter) addresses this need. The peripheral edge part of a lens group that does not retract when the lens group is stowed is removed in this Patent Literature 1. Consequently, the retracting lens group can be retracted to this removed part when the lens group is stowed. In Patent Literature 1 this was an attempt to achieve a more compact size while reducing the thickness in a stowed state.
However, with a conventional lens barrel such as that discussed in Patent Literature 1, since the retracting lens group is near the optical aperture position, the cross sectional shape of the light flux that passes through the retracting lens group inevitably ends up being substantially circular. Specifically, the peripheral edge part of the light flux passing through the retracting lens group cannot be removed. Accordingly, the lens barrel ends up being bulkier than a lens barrel that is not retracted when stowed.